Saab 2008 9-3 - Manual (Page 253)

253 Car care
Aspect ratio: A two-digit number that indi-
cates the tire height-to-width measure-
ments. For example, if the tire size aspect
ratio is “55”, as shown in item “C” of the illus-
tration, it would mean that the tire´s sidewall
is 55% as high as it is wide.
Belt Rating: A letter code is used to indicate
the type of ply construction in the tire. The
letter “R” means radial ply construction; the
letter “D” means diagonal or bias ply con-
struction; and the letter “B” means
belted-bias ply construction.
Rim Diameter: Diameter of the wheel in
inches.
Load range: The load range represents the
load carry capacity a tire is certified to carry.
Speed Rating: The maximum speed that a
tire is certified to carry a load. Speed ratings
range from “A” to “Z”.
Tire markings
An example of the meaning of the different
markings in a tire size is given below for a
tire size of 225/45 R17 94H:
225 Tire section width, mm
45
Aspect ratio, i.e. the section height
as a percentage of the section
width
R Radial ply
17
Wheel rim diameter 17 in at bead
seats
94 Tire load index
H Speed rating
Tire load indices
91
Tire approved for max. 1355 lbs.
(615 kg)
93 Max. 1433 lbs. (650 kg)
94 Max. 1477 lbs. (670 kg)
95 Max. 1521 lbs. (690 kg)
97 Max. 1609 lbs. (730 kg)
Speed ratings
Q
Tire approved for speeds up to
100 mph (160 km/h)
S Max. 112 mph (180 km/h)
T Max. 118 mph (190 km/h)
H Max. 130 mph (210 km/h)
V Max. 149 mph (240 km/h)
W Max. 168 mph (270 km/h)
Y Max. 186 mph (300 km/h)
93_US_M08.book Page 253 Friday, May 11, 2007 11:37 AM